This invention relates generally to vehicle transfer cases and, more particularly, to a transfer case providing full-time four wheel drive with limited slip between the front and rear drivelines.
Due to the recent growth in popularity of four wheel drive vehicles, part-time and full-time transfer cases have found increased application in passenger, sport and light duty vehicles. Many transfer cases include a differential mechanism for splitting torque between front and rear drivelines. For example, U.S. Pat. No. 4,677,873 issued to Eastman, entitled Transfer Case With Inter-Axle Dual-Planetary Differential, discloses a transfer case adapted for a two/four wheel drive vehicle which provides for an unequal torque split between the front and rear wheels during full-time four wheel drive operation. A dual-planetary differential gear set is shifted by means of a mode clutch to provide either four wheel drive with full-time differentiation between the front and rear wheels or a part-time four wheel drive operating mode wherein the dual planetary differential gear set is in a locked-up condition.